Seminars

Beyond Symbiosis: Reframing Of The UCYN-A Marine N2-fixing Partnership

Primary endosymbiosis is the biological process which led to the domestication of mitochondria and consequently the evolution of complex life on Earth. It is also responsible for the origin of the two photosynthetic organelles in eukaryotes which gave rise to land plants and many algal lineages. Research into marine microbes has revealed the fourth known occurrence of primary endosymbiosis which resulted in a novel N2-fixing organelle called the nitroplast. Candidatus Atelocyanobacterium thalassa, or UCYN-A, is a metabolically streamlined N2-fixing cyanobacterium previously reported to be an endosymbiont of a marine unicellular alga. Here we show that UCYN-A has been tightly integrated into algal cell architecture and organellar division and that it imports proteins encoded by the algal genome that expand its metabolic capabilities. For instance, UCYN-A biosynthetic pathways previously reported to be incomplete are restored by participation of nuclear-encoded proteins. The eukaryotic cell supports the process of N2-fixation with cytochrome P450 monooxygenases and flavodoxin electron-transfer proteins, and regulates UCYN-A circadian rhythm with cryptochromes. Furthermore, nuclear and nitroplast genomes together encode a vitamin B12 (adenosylcobalamin) biosynthetic pathway which may enable B. bigelowii to avoid B12 deficiency in the marine environment. This new perspective on a key player in the marine nitrogen cycle provides insight into the mechanisms of eukaryotic nitrogen fixation and the transition from symbiont to organelle.

 

Dr. Tyler Coale

Postdoctoral Researcher, UCSC

Dr. Tyler Coale is a postdoctoral researcher affiliated with UCSC and has previously studied the physiological response of phytoplankton in low iron conditions. Dr. Coale completed a B.S. in Plant Sciences at UCSC and went on to work as a technician in the field of chemical oceanography with Ken Bruland at UCSC and later with Kristen Buck at the Bermuda Institute of Ocean Sciences.

Shaping the Future of California Currents: Insights from Seasonal Forecasts to Climate Projections

The California Current Ecosystem (CCE) is a highly productive eastern boundary upwelling system, in which seasonal upwelling fuels primary production that supports a thriving marine ecosystem and socioeconomically valuable services including fisheries and tourism. The CCE and its resources are strongly driven by changes in the physical and biogeochemical environment, both of which experience considerable variability on timescales ranging from days to centuries. Prognostic information on this variability is therefore highly desirable for marine resource users, for example managers of fisheries whose target populations are sensitive to variations in the climate system. In this presentation, I will present a number of recent and ongoing efforts that have begun to explore the predictability and forecast skill of physical and biogeochemical properties in the CCE on seasonal-to-interannual (~1-24 months), decadal (~5- 20 years) and long-term (~50-100 years) timescales. I will also describe, when known, the physical mechanisms driving predictability in that range of timescales. Skillful forecasts and predictions of the physical and biogeochemical state in the CCE have the potential to provide actionable information to those managing the CC marine resources.

 

Dr. Mercedes Pozo Buil

Associate Project Scientist, UCSC/NOAA

Dr. Mercedes (Mer) Pozo Buil is a physical oceanographer interested in ocean modelling, climate change, ocean and climate dynamics, and decadal climate variability and its impact on marine ecosystems. She is an Associate Project Scientist at the University of California Santa Cruz in the Institute of Marine Sciences, working at the Ecosystem Science Division of the NOAA Southwest Fisheries Sciences Center in Monterey, California. Mer received two bachelor of science degrees in marine and environmental science, and a master’s degree in physical oceanography from the University of Cadiz in Spain. She holds a doctoral degree from the Georgia Institute of Technology.

Background

A collaborative sea otter study led by University of California, Santa Cruz, researchers is underway in Elkhorn Slough. Participating organizations and agencies include CDFW, USGS, Monterey Bay Aquarium, The Marine Mammal Center, ESNERR (ROMP), USFWS, and others. The purpose of the study is threefold: (1) to provide updated information on sea otter body condition, foraging success, and habitat use for comparison with data from a previous study conducted 2013–2016, (2) to provide novel information on sea otters’ physiological responses to stressors, and (3) to provide novel information on the social structure of sea otters. This fall, sea otter captures in Elkhorn Slough will occur for the third consecutive year. The goal is to recapture and resample sea otters tagged in previous years, replace missing tags, and capture new sea otters to add to the study. Sea otters will be captured primarily using tangle nets and transported to MLML Marine Operations for sedation, sampling, and tagging. After sampling and tagging are complete, the sedation will be reversed, and the sea otters will be transported back to their capture location and released. Monitoring of tagged sea otters is ongoing.

Engineering integrative methods for physiological sensing in whales.

High-resolution biologgers record detailed information about an animal in its natural environment and provide important information about species, like large-bodied whales, that are fully-aquatic and often difficult to observe. While traditional analyses of biologging tag data provide insights about an individual’s three-dimensional movement, recent engineered solutions are enabling direct measurements of physiological parameters, like heart rate, from non-invasive, suction-cup attached whale biologgers. Similarly, an increase in capacity for molecular analysis of tissue samples has uncovered the potential for unique adaptations at the cellular level to support the large body sizes, elevated breath-hold capacities, and extreme seasonal energetics of whales. Combining physiological rate measurements with information about cellular function and whole-organism diving behavior provides an unparalleled opportunity to understand the traits that underpin the extreme physiological function of cetaceans. This seminar will cover the “hows” and “whys” of physiological sensing in whales across multiple scales of biological organization and will conclude with major takeaways as to how these methods could be applied to benefit both comparative physiology as well as conservation and translational medicine.

 

Dr. Ashley Blawas

Postdoctoral Researcher, Hopkins Marine Station

Dr. Ashley Blawas is a postdoctoral researcher in the Goldbogen Lab at Hopkins Marine Station of Stanford University. She completed her B.S.E. in Biomedical Engineering at Duke University and her Ph.D. in Marine Science at the Duke University Marine Laboratory in the Nowacek Lab. She works at the intersection of marine mammal science, engineering, and ecological physiology to investigate the physiological traits that underpin the extreme metabolic function of cetaceans. To date, her work has led to new insights that inform our understanding of basic physiological principles as well as translational medicine and conservation. At Stanford she studies the physiology of baleen whales off the California coast using biologging tags and  has been developing the capacity for physio-logging by engineering novel designs for electrocardiogram (ECG) equipped tags. Her ongoing research also includes understanding the scaling of physiological rates in cetaceans and the molecular drivers of extreme cardiac function in diving baleen whales.

Emperors of the Ice: Physiological Ecology of the emperor penguin

Emperor penguins are the largest species of marine bird, and perhaps because of their size, they are able to fast longer, dive deeper, and endure harsher conditions than any other avian species. As a top predator in the Antarctic ecosystem, they have a significant top-down effect on prey. Additionally, as top predators, their survival and reproduction depend on the functioning of the entire food web.

Join Gitte McDonald as she talks about her research expeditions to the Ross Sea to study the ecology and physiology of emperor penguins. She will start off with an introduction to the basic biology and ecology of emperor penguins before talking about current research on the behavioral and physiological adaptations that allow them to thrive in the Antarctic ecosystem. The talk will conclude with a discussion of current and future challenges. The talk will be heavy on pictures and light on data.

 

Birgitte (Gitte) I. McDonald

Associate Professor, Moss Landing Marine Laboratories

As a physiological and behavioral ecologist, Dr. Gitte McDonald investigates adaptations that allow animals to survive in extreme environments. Marine mammals and birds provide an ideal study system to investigate how animals deal with extreme conditions because of their large size variation, geographic distribution, and physiological challenges they face daily, including hypoxia, extreme temperatures, and fasting. Understanding the mechanisms that allow an organism to interact and survive in its environment is crucial for predicting and potentially mitigating their response to climate change. Currently, her research program focuses on two broad areas of research: 1) determining the diving capacity of breath-hold divers and understanding the underlying mechanisms, and 2) determining the energetic requirements of foraging and reproduction to better understand energy allocation, physiological trade-offs, and the organism’s role in the ecosystem. To address these questions, she uses state-of-the-art biologgers that measure fine-scale diving behavior and physiological variables (heart rate and oxygen), in addition to providing information about the environment.  Her research has provided opportunities to work with a broad range of species in diverse habitats from the Antarctic to the Galapagos.

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Abstract:

The power of science for exploring the world depends on the research tools available and both the imagination and the rigor of the scientists using them. I will present three stories from my career that illustrate 1) the potential of using old tools in new ways, 2) the danger of a vivid imagination without sufficient scientific rigor, and 3) the importance of rigor over peer pressure. As a young marine scientist at UC Santa Cruz, I used SCUBA far offshore to study fragile aggregations of plankton and detritus--the so-call "marine snow" (1). SCUBA provided the manual dexterity and discrimination needed to selectively and carefully take samples, which differed from the traditional bottle-cast or net-towing methods at the time. At the time, this SCUBA sampling pushed the limits of what we knew about micro-environments in the pelagic environment, which expanded our understanding of fragile details on a milliliter scale--a scale relevant to larval fish and many zooplankton. We will discuss the implications and what I learned at NASA about never sending a person to do a job a robot can do better, faster, and cheaper. As a graduate student at Scripps, I considered the sinking of marine snow and studied the potential impact of temperature and pressure on marine bacteria in the Yayanos lab. At the time, a guest scientist, John Baross, was simulating the high temperature and high pressure conditions in hydrothermal vents and claimed to grow bacteria at 250°C and 265-bars pressure--far exceeding the known upper temperature limit of life at the time. Intrigued by his extraordinary result, I rigorously replicated his experiments and showed that all of the results could be explained by artifacts (2). While studying the upper temperature limit of life, I focused on the heat shock proteins (HSPs), that are found in all organisms and known to contribute to acquired thermotolerance. My research into the HSPs in an organism living in near boiling sulfuric acid led to a breakthrough in our understanding of the function of these highly conserved proteins in vivo (3, 4).

1. Silver, M.W., A.L. Shanks, and J.D. Trent. 1978. Marine snow: Microplankton habitat and source of small-scale patchiness in pelagic populations. Science 201: 371-373.

2. Trent, J.D., R.A. Chastain and A.A. Yayanos. 1984. Possible artefactual basis for apparent bacterial growth at 250°C. Nature 307:737-740.

3. Trent, J.D., et al. 1991. A chaperone from a thermophilic archaebacterium is related to the eukaryotic protein, t-complex polypeptide 1. Nature, 354(6353): 490-493.

4. 2003. Trent, Jonathan D., et al. 2003. Intracelluar localization of a group II chaperonin indicates a membrane-related function. Proceedings of the National Academy of Sciences, USA, 100: 15589-15594.

Bio:

After studying marine science at UC Santa Cruz, Jonathan, receive a PhD in Biological Oceanography at Scripps Institution of Oceanography. He conducted postdoctoral research at the Max Planck Institute for Biochemistry in Germany, Århus and Copenhagen Universities in Denmark and the University of Paris at Orsay in France. His research continued at the Boyer Center for Molecular Medicine at Yale Medical School and Argonne National Laboratory before joining NASA Ames Research Center. He left NASA in 2019 on a Fulbright at Akureyri University in Iceland and recently founded UpCycle Systems focused on building sustainable data centers. He is a Fellow at the California Academy of Sciences.

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Abstract:

Increases in atmospheric carbon dioxide levels have led to a global climate crisis, and reduction of fossil fuel emissions is no longer enough to prevent warming and other negative ecosystem impacts. To mitigate the damage, it now imperative to explore mechanisms to remove carbon dioxide from the atmosphere. The ocean has a large capacity to store carbon, exceeding that of the atmosphere by 50 times and that of soils and plants by 15-20 times. Consequently, there are many techniques that are being investigated to explore marine carbon dioxide removal (mCDR). Of these, ocean iron fertilization (OIF), is the most studied – due to extensive field testing of John Martin’s 1990 Iron Hypothesis. However, the use of OIF as a tool for mCDR is controversial, and there are many remaining uncertainties about its efficacy and its potential to impact ocean ecosystems. Due to these (and other) concerns, research evaluating OIF for mCDR was halted ~15 years ago. Today, the urgency of the climate crisis is causing this approach to be revisited. Here, I share a brief history of OIF research, and introduce the current and ongoing efforts of ExOIS (Exploring Ocean Iron Solutions): an organization comprised of oceanographers, international lawyers, and social scientists aimed at developing a strategy to evaluate OIF for mCDR. Plans for the next generation of field studies will be introduced, highlighting what’s new and what remains to be addressed scientifically, before OIF could be considered a viable climate solution or as a tool in the global C market.

 

Bio:

Sarah is the Biological Oceanography faculty member at Moss Landing Marine Laboratories. She studies the ecology, evolution, and physiology of marine phytoplankton. Phytoplankton are a diverse group of organisms and their photosynthesis fuels marine food webs, shaping biogeochemical cycles of carbon and other important elements (including nitrogen, iron, silica). Sarah’s research is largely focused on diatoms, an important and evolutionarily unique group of eukaryotic phytoplankton that often dominate coastal oceans and other nutrient-rich ocean environments. Diatoms are one of the most well-developed groups of model organisms for molecular studies, with several genomes and genetic tools currently available and Sarah’s research uses a wide variety of traditional and multi-omics tools to better understand the biology of diatoms and other phytoplankton in culture and field-based studies.

 

 

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Abstract:

The California Collaborative Fisheries Research Program (CCFRP) is a community-based science program that uses volunteer anglers and standardized hook-and-line fishing surveys to monitor responses of fish to marine protected areas (MPAs) across the state. With 15 years of data from Central California and 5 years of data statewide, we evaluate changes in catch per unit effort (CPUE), size structure, and biomass inside and outside MPAs over time and the effects of fishing pressure and MPA design attributes, such as age and size, on the strength of MPA responses. We found compelling evidence statewide that MPAs are working, when compared to reference sites. MPAs have elevated CPUE, larger fish body size, and higher biomass for the vast majority of fished species. Moreover, the magnitude of the MPA response is explained by the amount of fishing pressure occurring outside the MPA; stronger differences in fish biomass between MPA and reference sites occur in heavily fished areas. We also observed stronger MPA responses in larger and older reserves. Tag-recapture data provided evidence of spillover of some individuals across MPA boundaries, with presumed benefits to fisheries; however, our data indicated many fish species have small home ranges and stay within the boundaries of the MPAs. Finally, examination of CPUE and biomass trends with increasing distance from MPA boundaries indicates that fishing-the-line behavior and edge effects modify MPA responses in California.

 

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Abstract:

The modern fish farmer must weigh many, often conflicting, factors when making operational decisions on a farm site. They're balancing sales needs, resource limitations, and complex animal husbandry issues with a constantly changing set of ocean conditions on each farm. Technology is transforming this challenge through an ever-expanding IoT dataset (e.g., high resolution hydrographic sensors) and new tools like automated lice counting. In this talk we’ll look at how a group of oceanographers built software tools to translate the raw ocean observations into data-driven actions and behaviors to improve fish health and welfare on the farm sites. We’ll look at the ways ocean data analysis add confidence to feeding, treatment, and mitigation decisions as well as the process of founding the business.

Bio:

Jonathan LaRiviere is Chief Executive of Scoot Science, an ocean analytics and forecasting business based in Santa Cruz, California, which aims to help fish farmers protect assets, operate sustainably, and increase profits by enabling a more complete assessment of local ocean conditions. Scoot’s platform integrates in-pen sensors with external data sources to provide real-time information and forecasting for conditions in the marine environment. Jonathan co-founded Scoot in 2017 and was previously a lecturer at Santa Clara University. His research on reconstructing past ocean temperatures, CO2 levels and climate conditions to understand how the oceans and earth systems respond to climate change has been published in Nature, Nature Geoscience, Science, and Geophysical Research Letters. He holds a PhD in Ocean Sciences from UCSC.

 

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Abstract:

In the past two decades compound-specific isotope analysis of amino acids (CSI-AA) has exploded, moving from a novel analysis performed by a few labs to an increasingly mainstream technique, employed across a steadily increasing range of disciplines from ecology, archaeology, paleoceanography, geomicrobiology, and biogeochemical cycle research. Amino acid stable carbon (13CAA) and nitrogen (15NAA) measurements remain the best developed applications, with D/H ratios of AA  and molecular position-specific isotopes representing the next frontier. Most work to date has focused on establishing trophic connectivity and baseline isotope values in modern and palaeoecological applications. This talk will present an overview CSI-AA techniques and potential applications, focused primarily on coupling 15NAA and 13CAA potential to establish trophic connectivity, primary production and nutrient sources at the base of food webs, and applications coupling CSI-AA with isoscape to understand animal migration or shifts in feeding zones.  Finally, it will focus on new potential and emerging applications, such as exploring symbioses in extant organisms as well as microfossils.

Bio:

Mathew McCarthy is a marine organic geochemist and  Professor of Oceanography at University of California Santa Cruz.   A chemist by training, he studied bio- and organic chemistry at UC San Diego Rodger Revelle college, followed by two years working as a chemist on  Methyl Mercury contamination in the Mediterranean at the International Atomic Agency - Marine Environmental Studies Laboratory in Monaco.  Returning to the US, he received his PhD from University of Washington in Oceanography and Organic Geochemistry in 1998, working with John Hedges on new approaches to understand structures and bioavailability of marine dissolved organic matter.  After his PhD he received a Chateaubriand Fellowship to study in Paris, was then a Carnegie postdoctoral fellow at the Carnegie Geophysical lab in Washington DC,  and finally received a University of Hawaii young investigator award to work on interactions between microbial loop processes and DOM production, before coming to UC Santa Cruz as an assistant professor in 2001.

The McCarthy Lab focuses on developing and applying organic and stable isotope methods to address a wide range of biogeochemical, paleo-oceanographic and ocean ecology questions.   A main focus has been developing compound-specific amino acid isotope techniques and approaches